Keepalived模式是抢占模式还是非抢占模式 keepalived stop

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mob6454cc7b3ae8 2024-08-09 19:12:47

文章标签 linux html 高可用 TCP 文章分类 运维

文章目录

keeplived高可用

1.keeplived简介
2.keeplived的重要功能
3.keepalived高可用故障转移的原理
4.keepalived工作原理描述
5.keepalived实现nginx负载均衡高可用

5.1.keepalived安装
5.2.在slave上安装keepalived
5.3.在主和备主机上分别安装httpd
5.4.keepalived配置
5.5.查看VIP
5.6.让keepalived监控httpd负载均衡
5.7.配置keepalived加入监控脚本的配置
5.8.访问测试

模拟主服务器挂掉

keeplived高可用

1.keeplived简介

Keepalived 软件起初是专为LVS负载均衡软件设计的，用来管理并监控LVS集群系统中各个服务节点的状态，后来又加入了可以实现高可用的VRRP功能。因此，Keepalived除了能够管理LVS软件外，还可以作为其他服务（例如：Nginx、Haproxy、MySQL等）的高可用解决方案软件。

Keepalived软件主要是通过VRRP协议实现高可用功能的。VRRP是Virtual Router RedundancyProtocol(虚拟路由器冗余协议）的缩写，VRRP出现的目的就是为了解决静态路由单点故障问题的，它能够保证当个别节点宕机时，整个网络可以不间断地运行。

所以，Keepalived 一方面具有配置管理LVS的功能，同时还具有对LVS下面节点进行健康检查的功能，另一方面也可实现系统网络服务的高可用功能。

keepalived官网

2.keeplived的重要功能

keepalived 有三个重要的功能，分别是：

管理LVS负载均衡软件
实现LVS集群节点的健康检查
作为系统网络服务的高可用性（failover）

3.keepalived高可用故障转移的原理

Keepalived 高可用服务之间的故障切换转移，是通过 VRRP (Virtual Router Redundancy Protocol ,虚拟路由器冗余协议）来实现的。

在 Keepalived 服务正常工作时，主 Master 节点会不断地向备节点发送（多播的方式）心跳消息，用以告诉备 Backup 节点自己还活看，当主 Master 节点发生故障时，就无法发送心跳消息，备节点也就因此无法继续检测到来自主 Master 节点的心跳了，于是调用自身的接管程序，接管主 Master 节点的 IP 资源及服务。而当主 Master 节点恢复时，备 Backup 节点又会释放主节点故障时自身接管的IP资源及服务，恢复到原来的备用角色。

那么，什么是VRRP呢？
VRRP ,全称 Virtual Router Redundancy Protocol ,中文名为虚拟路由冗余协议，VRRP的出现就是为了解决静态踣甶的单点故障问题，VRRP是通过一种竞选机制来将路由的任务交给某台VRRP路由器的。

4.keepalived工作原理描述

Keepalived高可用对之间是通过VRRP通信的，因此，我们从 VRRP开始了解起：

VRRP,全称 Virtual Router Redundancy Protocol,中文名为虚拟路由冗余协议，VRRP的出现是为了解决静态路由的单点故障。
VRRP是通过一种竟选协议机制来将路由任务交给某台 VRRP路由器的。
VRRP用 IP多播的方式（默认多播地址（224.0_0.18))实现高可用对之间通信。
工作时主节点发包，备节点接包，当备节点接收不到主节点发的数据包的时候，就启动接管程序接管主节点的开源。备节点可以有多个，通过优先级竞选，但一般 Keepalived系统运维工作中都是一对。
VRRP使用了加密协议加密数据，但Keepalived官方目前还是推荐用明文的方式配置认证类型和密码。

介绍完 VRRP,接下来我再介绍一下 Keepalived服务的工作原理：

Keepalived高可用是通过 VRRP 进行通信的， VRRP是通过竞选机制来确定主备的，主的优先级高于备，因此，工作时主会优先获得所有的资源，备节点处于等待状态，当主挂了的时候，备节点就会接管主节点的资源，然后顶替主节点对外提供服务。
在 Keepalived 服务之间，只有作为主的服务器会一直发送 VRRP 广播包,告诉备它还活着，此时备不会枪占主，当主不可用时，即备监听不到主发送的广播包时，就会启动相关服务接管资源，保证业务的连续性.接管速度最快可以小于1秒。

5.keepalived实现nginx负载均衡高可用

环境说明

系统类型	主机名	IP
centos8	master	192.168.100.146
centos8	slave	192.168.100.148

本次高可用虚拟IP（VIP）地址暂定为 192.168.100.250

5.1.keepalived安装

配置master的keepalived

关闭防火墙

[root@master ~]# systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@master ~]# setenforce 0
[root@master ~]# sed -ri 's/^(SELINUX=).*/\1disabled/g' /etc/selinux/config
[root@master ~]# reboot

下载epel源并安装相应工具

[root@master ~]# yum -y install epel-release vim wget

安装keepalived

[root@master ~]# yum -y install keepalived

查看安装生成的文件

[root@master ~]# rpm -ql keepalived
/etc/keepalived
/etc/keepalived/keepalived.conf
/etc/sysconfig/keepalived
/usr/bin/genhash
/usr/lib/.build-id
/usr/lib/.build-id/0a
/usr/lib/.build-id/0a/410997e11c666114ca6d785e58ff0cc248744e
略。。。。。。
/usr/share/man/man1/genhash.1.gz
/usr/share/man/man5/keepalived.conf.5.gz
/usr/share/man/man8/keepalived.8.gz
/usr/share/snmp/mibs/KEEPALIVED-MIB.txt
/usr/share/snmp/mibs/VRRP-MIB.txt
/usr/share/snmp/mibs/VRRPv3-MIB.txt
[root@master ~]#

5.2.在slave上安装keepalived

关闭防火墙和selinux

[root@slave ~]#  systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@slave ~]# setenforce 0
[root@slave ~]# sed -ri 's/^(SELINUX=).*/\1disabled/g' /etc/selinux/config
[root@slave ~]# reboot

下载epel源并安装相应工具

[root@slave ~]# yum -y install epel-release vim wget

安装keepalived

[root@slave ~]# yum -y install keepalived

查看安装生成的文件

[root@slave ~]# rpm -ql keepalived
/etc/keepalived
/etc/keepalived/keepalived.conf
/etc/sysconfig/keepalived
/usr/bin/genhash
/usr/lib/.build-id
/usr/lib/.build-id/0a
/usr/lib/.build-id/0a/410997e11c666114ca6d785e58ff0cc248744e
略。。。。。。
/usr/share/man/man1/genhash.1.gz
/usr/share/man/man5/keepalived.conf.5.gz
/usr/share/man/man8/keepalived.8.gz
/usr/share/snmp/mibs/KEEPALIVED-MIB.txt
/usr/share/snmp/mibs/VRRP-MIB.txt
/usr/share/snmp/mibs/VRRPv3-MIB.txt
[root@slave ~]#

5.3.在主和备主机上分别安装httpd

master

[root@master ~]# yum -y install httpd
[root@master ~]# cd /var/www/html/
[root@master html]# ls
[root@master html]# echo 'master' > index.html
[root@master html]# systemctl start httpd
[root@master html]# systemctl enable httpd
Created symlink /etc/systemd/system/multi-user.target.wants/httpd.service → /usr/lib/systemd/system/httpd.service.
[root@master html]# ss -antl
State    Recv-Q   Send-Q      Local Address:Port            Peer Address:Port         Process         
LISTEN   0        128               0.0.0.0:22                   0.0.0.0:*                            
LISTEN   0        128                     *:80                         *:*                            
LISTEN   0        128                  [::]:22                      [::]:*                            
[root@master html]#

slave

[root@slave ~]# yum -y install httpd
[root@slave ~]#  cd /var/www/html/
[root@slave html]# ls
[root@slave html]# echo 'slave' > index.html
[root@slave html]# systemctl start httpd
[root@slave html]#  systemctl enable httpd
Created symlink /etc/systemd/system/multi-user.target.wants/httpd.service → /usr/lib/systemd/system/httpd.service.
[root@slave html]# ss -antl
State    Recv-Q   Send-Q      Local Address:Port            Peer Address:Port         Process         
LISTEN   0        128               0.0.0.0:22                   0.0.0.0:*                            
LISTEN   0        128                     *:80                         *:*                            
LISTEN   0        128                  [::]:22                      [::]:*                            
[root@slave html]#

访问试试，确保master上的httpd服务能够正常访问

[root@master html]# curl 192.168.100.146
master
[root@master html]#

[root@slave html]# curl 192.168.100.148
slave
[root@slave html]#

5.4.keepalived配置

在master上配置

[root@master ~]# vi /etc/keepalived/keepalived.conf
[root@master ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb01
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass chenshunli
    }
    virtual_ipaddress {
        192.168.100.250
    }
}

virtual_server 192.168.100.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.146 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.100.148 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

[root@master ~]# 
[root@master ~]# systemctl start keepalived
[root@master ~]# systemctl enable keepalived
Created symlink /etc/systemd/system/multi-user.target.wants/keepalived.service → /usr/lib/systemd/system/keepalived.service.
[root@master ~]#

在slave上配置

[root@slave ~]# vi /etc/keepalived/keepalived.conf
[root@slave ~]# cat /etc/keepalived/keepalived.conf 
! Configuration File for keepalived

global_defs {
   router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass wangqing
    }
    virtual_ipaddress {
        192.168.100.250
    }
}

virtual_server 192.168.100.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.146 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.100.148 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@slave ~]# 
[root@slave ~]# systemctl start keepalived
[root@slave ~]# systemctl enable keepalived
Created symlink /etc/systemd/system/multi-user.target.wants/keepalived.service → /usr/lib/systemd/system/keepalived.service.
[root@slave ~]#

5.5.查看VIP

在master上查看

[root@master ~]# ip a 
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:d0:d1:3d brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.146/24 brd 192.168.100.255 scope global dynamic noprefixroute ens33
       valid_lft 1452sec preferred_lft 1452sec
    inet 192.168.100.250/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::cf6b:868a:4633:4bb0/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@master ~]#

在slave上查看没有

[root@slave ~]# ip a 
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:fd:cd:90 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.148/24 brd 192.168.100.255 scope global dynamic noprefixroute ens33
       valid_lft 1657sec preferred_lft 1657sec
    inet6 fe80::cfeb:3fe4:99b:3ec2/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@slave ~]#

5.6.让keepalived监控httpd负载均衡

在master上编写

[root@master ~]# mkdir /scripts
[root@master ~]# cd /scripts/
[root@master scripts]# vim check_httpd.sh
[root@master scripts]# cat check_httpd.sh
#!/bin/bash
httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l)
if [ $httpd_status -lt 1 ];then
    systemctl stop keepalived
fi
[root@master scripts]# 
[root@master scripts]# chmod +x check_httpd.sh
[root@master scripts]# vim notify.sh
[root@master scripts]# cat notify.sh
#!/bin/bash
VIP=$2
sendmail (){
        subject="${VIP}'s server keepalived state is translate"
        content="`date +'%F %T'`: `hostname`'s state change to master"
        echo $content | mail -s "$subject" 3199560936@qq.com
}
case "$1" in
  master)
        httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l)
        if [ $httpd_status -lt 1 ];then
            systemctl start httpd
        fi
        sendmail
  ;;
  backup)
        httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l)
        if [ $httpd_status -gt 0 ];then
            systemctl stop httpd
        fi
  ;;
  *)
        echo "Usage:$0 master|backup VIP"
  ;;
esac
[root@master scripts]# 
[root@master scripts]# chmod +x notify.sh
[root@master scripts]# ll
总用量 8
-rwxr-xr-x 1 root root 143 10月 21 04:01 check_httpd.sh
-rwxr-xr-x 1 root root 662 10月 21 04:03 notify.sh
[root@master scripts]#

在slave上编写

[root@slave ~]# mkdir /scripts
[root@slave ~]# cd /scripts/
[root@slave scripts]# vi notify.sh
[root@slave scripts]# cat notify.sh 
#!/bin/bash
VIP=$2
sendmail (){
        subject="${VIP}'s server keepalived state is translate"
        content="`date +'%F %T'`: `hostname`'s state change to master"
        echo $content | mail -s "$subject" 3199560936@qq.com
}
case "$1" in
  master)
        httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l)
        if [ $httpd_status -lt 1 ];then
            systemctl start httpd
        fi
        sendmail
  ;;
  backup)
        httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l)
        if [ $httpd_status -gt 0 ];then
            systemctl stop httpd
        fi
  ;;
  *)
        echo "Usage:$0 master|backup VIP"
  ;;
esac
[root@slave scripts]# chmod +x notify.sh 
[root@slave scripts]# ll
总用量 4
-rwxr-xr-x 1 root root 662 10月 21 04:05 notify.sh
[root@slave scripts]#

此处的脚本名称应避免与服务名相同，推荐用服务名的首字母代替，如check_n，不要给脚本起名check_nginx

5.7.配置keepalived加入监控脚本的配置

配置master

[root@master ~]# vi /etc/keepalived/keepalived.conf
[root@master ~]# cat /etc/keepalived/keepalived.conf
onfiguration File for keepalived

global_defs {
   router_id lb01
}

vrrp_script httpd_check {
    script "/scripts/check_httpd.sh"
    interval 1
    weight -20
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass shenlongfei
    }
    virtual_ipaddress {
        192.168.100.250
    }
    track_script {
        httpd_check
    }
    notify_master "/scripts/notify.sh master 192.168.100.250"
    notify_backup "/scripts/notify.sh backup 192.168.100.250"
}

virtual_server 192.168.100.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.146 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.100.148 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@master ~]# 
[root@master ~]# systemctl restart keepalived
[root@master ~]#

在slave上编写

[root@slave ~]# vi /etc/keepalived/keepalived.conf
[root@slave ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 52
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass shenlongfei
    }
    virtual_ipaddress {
        192.168.100.250
    }
    notify_master "/scripts/notify.sh master 192.168.100.250"
    notify_backup "/scripts/notify.sh backup 192.168.100.250"
}

virtual_server 192.168.100.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.146 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.100.148 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@slave ~]# systemctl restart keepalived
[root@slave ~]#

5.8.访问测试

模拟主服务器挂掉

先测试master发现找不到服务，并且没有VIP

[root@master ~]# ip a 
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:d0:d1:3d brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.146/24 brd 192.168.100.255 scope global dynamic noprefixroute ens33
       valid_lft 1156sec preferred_lft 1156sec
    inet6 fe80::cf6b:868a:4633:4bb0/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@master ~]#

Keepalived模式是抢占模式还是非抢占模式 keepalived stop_html

再测试salve，发现可以访问，并且VIP能看到

[root@slave ~]# ip a 
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:fd:cd:90 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.148/24 brd 192.168.100.255 scope global dynamic noprefixroute ens33
       valid_lft 1353sec preferred_lft 1353sec
    inet 192.168.100.250/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::cfeb:3fe4:99b:3ec2/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@slave ~]#

Keepalived模式是抢占模式还是非抢占模式 keepalived stop_linux_02